A common practice in forming fibers of mineral material, such as glass, is to discharge molten glass from a forehearth into a rotating centrifuge or spinner. The molten glass flows across the spinner bottom wall to the spinner peripheral wall and passes in a molten state through the orifices of the spinner peripheral wall to create glass fibers. In some of the fiber producing apparatus, burners are positioned to direct flows of hot gases or products of combustion into contact with the molten glass within the spinner, and with the spinner bottom and peripheral walls to maintain the glass at a sufficiently elevated temperature for proper fiberizing.
One of the problems with fiberizers utilizing internal burners is that it is difficult to maintain a uniform temperature along the entire height of the spinner peripheral wall. The top portion of the spinner peripheral wall is too cool for proper fiberization, and results in fibers which are too large in diameter. Also, the air currents created by the blower external from the spinner can result in a flow of relatively cool gases adjacent the lower portion of the spinner peripheral wall, thereby increasing the temperature gradient along the height of the spinner peripheral wall. Another problem involved with fiberizers utilizing an internal burner is that of disposing of the gases of combustion after they have impinged on the glass and spinner bottom and peripheral walls.
This invention is directed toward the solution of the above problems by providing an opening in the spinner for venting the hot gases from the spinner, and means for directing the vented hot gases toward the spinner peripheral wall.